Knit & Crochet Show attendees won’t be the only ones wearing sweaters this weekend; Elm Street trees, lamp posts, signs and bus stop benches will be wrapped in yarn too.

The Knit & Crochet Show hits Manchester Wednesday, July 23, through Sunday, July 27, at the Radisson Center. The event includes workshops, classes and exhibition booths produced by some of the best knitters and crocheters in the world. (Lily Chin will be one of those instructors; deemed the “fastest crocheter in the world,” she was a guest on Late Night with Dave Letterman in 2008 and created a sweater for the comedian during the one-hour show.)

But this year’s event, sponsored by the Crochet Guild of America, will also include a few whimsical surprises scattered about the venue. Come July 23, Guild members will have created decorated fiber squares to scatter and coat the Radisson Center’s front grounds and inside lobby.

“We’re doing a yarn bomb in honor of the Crochet Guild of America’s 20th anniversary,” said Jennifer Ryan, a guild member and Manchester resident, who’s organizing the outdoor and indoor yarn display.

Ryan is also a crochet designer; much of her work has been featured in crochet and yarn company magazines, and she was heavily involved with last year’s outdoor fiber arts installation at the Currier Museum of Art, part of its Art Fest celebration. She suggested the idea to Knit & Crochet Show organizers when she heard the event would happen in Manchester again. They agreed and put out a nationwide call to artists.

At the time of the interview, Ryan was busy collecting, organizing and delegating the design and layout of the installation, which includes more than 500 crocheted squares, donated by guild members and local crocheters to decorate the grounds.

“Benches, trees, lamp posts — those are some of the things we’ll be covering,” Ryan said. “There are small bamboo trees and a garden inside the hotel lobby — we’ll decorate those, as well as the furniture in the lounge, the lamps and railings, and of course, the front desk.”

Some of the squares were made with specialty yarn, made to look like glittery fur; some are 3-D, with flowers bursting from the seams. Others contain New Hampshire icons. (One square depicts an alien face, made in honor of Anita and Benny Hill, a couple who claimed to have been abducted by extraterrestrials in New Hampshire, 1961.) Others sport the number 20 in honor of the Guild’s 20th anniversary.

Red Heart Yarn is sponsoring the bomb, and if you’ve missed the memo before its start, the company will donate yarn on-site for crocheters to make something to add.

It’s helped, Ryan said, that the Currier’s 2013 Art Fest contained an outdoor fiber arts installation; the community art project offered up a whimsical, surprising way to view yarn, not just as something to keep people warm, but as art to admire. It was these photos she showed to event organizers and to the Radisson; she thinks that because of last year’s event, people are more open-minded to the idea.

“Someone at the event last year said, ‘This is the kind of art that makes you smile.’ I love how yarn bombings show off how versatile crochet, specifically, can be,” Ryan said. “It’s displayed in ways you wouldn’t expect.”

After July 27, community crochet and knitting groups will stitch together the yarn bomb’s decor and create blankets to donate.

The show as a whole, according to guild member and Merrimack resident Pat Heinrich, is a crocheter’s paradise. She’s been involved with CGOA for more than 10 years and admires how the event, every time she attends, enables her to learn more about the craft, whether it be new techniques (hairpin lace, for instance) or new inspirations.

Every year, she walks away totally energized and invigorated.

“Everybody there is wearing crochet, even in the summer,” said Heinrich, who also facilitates a crochet group in Merrimack. “Short-sleeved sweaters, socks, pants, skirts, dresses, shawls, scarves, shrugs, flip flops — the only thing you won’t see them wearing is blankets.”

There’s a “serenity zone” for knitters and crocheters, Ryan explained, a sort of social group where people sit, knit and chat. In addition to the many technique classes, there will be booths with vendors from all over the country, a fashion show, competitions and social events, open to guild members and also general yarn enthusiasts. Admission is $5 to enter the expo, and for the most part, you can enter a class the day of, as long as it’s not already full.